1. Field of the Invention
This invention relates generally to wireless telecommunication, and more particularly to location services.
2. Background of Related Art
WiFi is a wireless area local network technology that enables a wireless device to exchange data or connect to the Internet using radio frequency (RF) waves, e.g., 2.4 GHz UHF and 5 GHz SHF. WiFi is synonymously known as WLAN (wireless local area network).
A wireless Access Point (AP) is a device that enables wireless WiFi-enabled devices to connect to a wired network using Wi-Fi, or related standards. The AP usually connects to a WiFi AP controller, or router, via a wired network as a standalone device, but it can also be an integral component of the router itself.
WiFi access points and AP controllers are known. Commercial entities such as CISCO™ and QUALCOMM™ have developed AP controllers with location determination engines to locate a WiFi enabled wireless device. The location determination engines receive a signal strength indication and/or round trip time (RSSI/RTT) measurement from the access points (AP). Using such techniques, each Access Point (AP) reports the RSSI/RTT to the WiFi AP Controller they are attached to. The AP Controller can perform trilateration for a single WiFi enabled wireless device based on the measurements from multiple access points (AP).
FIG. 8 shows a conventional WiFi enabled wireless device in range and communication with several access points (AP).
In particular, as shown in FIG. 8, a WiFi enabled wireless device 401, e.g., a wireless phone is in range of a plurality of access points 410. Each of the access points (AP) 410 are in communication with a WiFi AP controller 420. The Access points may be dispersed about an internal building space, e.g., a shopping mall.
Only the MAC address of the WiFi enabled wireless device 801 is known to the AP controllers 820. Thus, position locating is local within each WiFi AP controller 820, permitting the conventional WiFi location techniques to work very well in a single venue. But the present inventors have realized that while conventional WiFi location techniques do not scale across venues, there would be advantage to having WiFi positioning available to network location based services.